Flatten mesh from uv's to retopo in blender 2.8
Wow so i got it, a bit weird process but I got it. you first have to use tex tools to flatten it. after that, you duplicate the flatten mesh. then delete shapekeys on flatten mesh of the duplicated version. then export the duplicated mesh. as i think obj might have been fbx. but point is it has to have shading on it. so reimport it. then on the new imported add a shapekey from the flattened uv version. so it blends back onto the mesh. then on the new imported version with shading. retopo on it. i used retopoflow alpha but you can use your choice of retopo workflow. after i applied on the retopoflow modifers. then added shrinkwrap on the retopo. then i just used the shape keys to put it back on mesh. then you can apply the shrinkwrap i believe then export from there.